HC4900 Load Moment Indicator Main Controller (Part No.207324) for XCMG QY70K Crane

Product Overview

The HC4900 load moment indicator (LMI) main controller is the core processing unit of the crane safety monitoring system, built to Hirschmann factory specification as a direct replacement for part number 207324. Designed specifically for XCMG K-series hydraulic truck cranes, this control unit integrates seamlessly with the original wiring harness, sensor network and cabin display of QY70K and other same-platform models, delivering performance fully consistent with original equipment.

At its core is a 32-bit industrial processor running a real-time multi-task operating system. The unit pulls live data from boom length sensors, angle sensors, hydraulic pressure transducers and hoist limit switches, then dynamically calculates actual lifting load and working moment in real time. It cross-references these values against the crane factory load chart to judge operating status, and triggers graded alarms and control outputs to prevent overload incidents and protect both personnel and equipment on site.

Core Safety & Control Functions

• Real-time Load Calculation: Continuously processes multi-channel sensor signals to compute actual lifting capacity and moment ratio, with low-latency data output to the cabin display for operator reference.

• Three-stage Protection Logic: The system follows a standard tiered warning flow. At 90% of rated capacity, a yellow pre-warning activates to remind operators to proceed with caution. At 100% rated load, a red visual alarm and audible buzzer trigger, and all crane movements that increase lifting moment are automatically locked out to stop dangerous operation.

• Built-in Self-diagnosis: Full system self-check runs on power-up, and real-time monitoring covers sensor communication, internal hardware status and supply voltage. Clear fault codes are output for common issues such as sensor disconnection, signal abnormality and voltage fluctuation, simplifying on-site troubleshooting.

• CANopen Bus Communication: Adopts standard CANopen 2.0B protocol for stable, interference-resistant data transmission between the controller, display unit and all field sensors, suitable for the harsh electrical and physical environment of construction sites.

Technical Specifications

• Processor: 32-bit industrial-grade CPU, 40MHz

• Memory: 4MB program storage, 2MB data storage

• Power input: DC 10–36V wide voltage range

• Typical current draw: 120mA at 24V

• Interfaces: 1 × CANopen 2.0B, 1 × RS232

• I/O: 4 digital inputs, 4 digital outputs

• Enclosure rating: IP65 dust and water resistant

• Operating temperature: -40°C to +85°C

• Certifications: CE certified, compliant with GB12602-2009 and GB7950 standards

Application & Compatibility

This HC4900 controller (part number 207324) is factory-matched for the XCMG QY70K telescopic boom truck crane. It is also fully interchangeable with other XCMG K-series crane models — including QY25K, QY50K and QY50K-I — that share the same Hirschmann LMI system architecture. It serves as a direct drop-in replacement for damaged or faulty original control units, requiring no modification to existing mounting brackets or wiring harnesses, making it suitable for both routine maintenance and emergency breakdown repair.

Field-proven Reliability

As the brain of the crane load moment protection system, the HC4900 controller directly determines the reliability of onboard safety functions. This unit uses industrial-grade electronic components housed in a rugged sealed metal enclosure, built to withstand constant vibration, heavy dust, high humidity and wide temperature swings common in heavy lifting and construction operations. Its mature control algorithm has been validated across years of field application on XCMG cranes worldwide, providing consistent, accurate overload protection for daily lifting work.